Is Sydney the capital of Australia, and if not, why not?

Just for reference, the capital of Australia is Canberra.

Sydney is not the capital city, even though, yes, it is the largest. The reason is because Melbourne was the financial centre of Australia, but Sydney was the largest city. There was some conflict because Sydney felt they should be the capital, so eventually, the government decided to give neither city the status of capital. So in 1927, when Canberra was completed (halfway between Sydney and Melbourne) it became the capital. This is also the reason as to why the Australian Capital Territory exists, so then it would be in neither New South Wales or Victoria.

In the first day of January 1901, the colonies of New South Wales, Victoria, South Australia, Queensland, Western Australia and Tasmania joined together in a new Commonwealth of Australia. Both before and after Federation, there was much public bickering about what and where a federal territory and Seat of Government should be. The Constitution said that the Parliament must choose a site at least one hundred miles (160km) from Sydney and that the Parliament would sit in Melbourne until a new parliament house was built in the new capital ...

A ‘new’ site at Yass-Canberra emerged as an acceptable compromise. This large district was almost exactly a ‘hundred miles’ (160km) from Sydney and offered clean air, a good water supply and an invigorating climate. If the Federal Parliament would change its mind in favour of Canberra, New South Wales would provide land on the coast so that a federal city could have its own seaport at Jervis Bay. In October 1908, the Seat of Government Bill, confirming Yass-Canberra as the nation’s capital, was passed by the Parliament ...

In 1913, when the Canberra area was no more than an outback sheep station divided by the Molonglo River, a ceremony was held to name the city. ‘Canberra’, as a new name for the capital, was a sentimental favourite and logical choice. The name probably derived from a local Aboriginal word for ‘meeting place’ and had been in common use in the district for more than three-quarters of a century.

https://www.nca.gov.au/education/canberras-history/siting-and-naming-canberra#